JP2016178994A - Cardiac magnetic field analysis device, cardiac magnetic field analysis system, and cardiac magnetic field analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cardiac magnetic field analysis device for effectively analyzing a cardiac magnetic signal.SOLUTION: A cardiac magnetic field analysis device includes a current arrow generation part for generating a plurality of current arrows which are vector of a current flowing in a cardiac magnetic field from a cardiac magnetic field signal measured by a magnetocardiograph, a vector loop generation part for generating a cardiac magnetic field vector loop showing an x component and a y component of the plurality of generated current arrows in coordinates, and an input/out processing part for displaying the generated cardiac magnetic field vector loop in a display device. The input/out processing part displays the generated cardiac magnetic field vector loop in the display device, changing the display according to a predetermined condition. When a channel is designated through an input device, a cardiac magnetic field vector loop eliminating the channel is generated and displayed.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a technique for a magnetocardiogram analysis apparatus, a magnetocardiogram analysis system, and a magnetocardiogram analysis method for analyzing a magnetocardiogram signal.

Vector electrocardiograms are known as a method for three-dimensionally analyzing electromotive force obtained from an electrocardiogram (for example, Non-Patent Document 1 and Non-Patent Document 2).
Further, Non-Patent Document 3 describes a color vector electrocardiogram for color-coding a vector electrocardiogram according to the electromotive force potential.

Junichi Yoshikawa, Hiroshi Kasuki, Kazuo Doshi, Shintaro Beppu, Matsusaki Masutoku, “Healthcare Practice 5 Solving with ECG”, Tokyo Bunkodo Hongo, Jun. 1995, p.37-39 Hiroaki Mori, “Heart Disease and Kiken's Home Page Chapter 1 What is Vector ECG?” [Online], [Search August 28, 2014], Internet <URL: http: //www.udatsu.vs1. jp / vcg-what.htm> Junji Kinoshita, “3D display of electrocardiogram 1. Color vector electrocardiogram”, [online], [Search August 28, 2014], Internet <URL: http://www5f.biglobe.ne.jp/~kinosita/ ecgb.htm>

  However, in the vector electrocardiogram, since all of the 12-lead electrocardiograms must be used, an operation such as creating a vector electrocardiogram without using a noisy electrocardiogram is impossible.

  The present invention has been made in view of such a background, and an object of the present invention is to provide an analysis method capable of detecting and displaying a minute vector change with high sensitivity using a magnetocardiogram signal.

  In order to solve the above-described problems, the present invention is characterized in that a vector ring is generated in which unit vector components of a current arrow (current vector) generated from a magnetocardiogram signal are plotted.

  According to the present invention, a minute vector change can be detected and displayed with high sensitivity using a magnetocardiogram signal.

It is a figure which shows the example of whole structure of the biomagnetic field measurement system which concerns on this embodiment. It is a figure which shows the structural example of a cryostat. It is a figure which shows arrangement | positioning of the SQUID magnetometer at the time of a measurement. It is a figure which shows the structural example of the arithmetic unit which concerns on 1st Embodiment. It is a flowchart which shows the procedure of the magnetocardial vector ring analysis process which concerns on 1st Embodiment. It is a figure which shows the production | generation method of the magnetocardial vector ring which concerns on 1st Embodiment. It is a figure which shows the example of a screen concerning 1st Embodiment. It is an enlarged view of a magnetocardiogram vector ring display screen. It is a figure which shows the example of the magnetocardial vector ring in P wave. It is a figure which shows the example of the current arrow diagram display screen from which the channel considered that the noise has arisen was removed. It is a figure which shows the example of the magnetocardial vector ring regarding J wave detection. It is a figure which shows the example of the magnetocardiogram vector ring regarding WPW (Wolf-Parkinson-White) syndrome. It is a flowchart which shows the procedure of the magnetocardiogram vector ring analysis process which concerns on 2nd Embodiment. It is a figure which shows the example of the current arrow diagram display screen where the channel was selected. It is a figure which shows arrangement | positioning of the SQUID magnetometer at the time of the measurement which concerns on 3rd Embodiment. It is a figure which shows the magnetocardial vector ring screen which concerns on 3rd Embodiment.

  Next, modes for carrying out the present invention (referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.

<< First Embodiment >>
First, a first embodiment according to the present invention will be described with reference to FIGS.

(System Configuration)
FIG. 1 is a diagram illustrating an overall configuration example of a biomagnetic field measurement system according to the present embodiment.
Each configuration of the biomagnetic field measurement system (cardiac magnetic field analysis system) Z is arranged separately inside and outside the magnetic shield room 5.
In the magnetic shield room 5, a plurality of SQUID (Superconducting Quantum Interference Device) magnetometers are arranged inside and held at a cryogenic temperature, a gantry 3 holding the cryostat 2, and a subject ( A bed 4 on which a not shown) lies is arranged. The bed 4 can move in the short axis direction (y direction), move in the long axis direction (x direction), and move in the vertical direction (z direction), and can easily align the measurement area of the cryostat 2. Can be done. The cryostat 2 and the gantry 3 may be collectively referred to as a magnetic field measuring device 6.

Outside the magnetic shield room 5, there are a drive circuit 7 for driving a plurality of SQUID magnetometers arranged in the cryostat 2, an amplifier filter unit 8 for amplifying and filtering the output from the drive circuit 7, and an amplifier filter The output signal from the unit 8 is collected, the collected magnetocardiogram signal is analyzed, and the arithmetic unit (cardiac magnetic field analyzer) 1 that controls each part of the magnetic field measuring device 6 is analyzed and processed by the arithmetic unit 1. A display device 9 for displaying the analysis results is mainly arranged.
In the present embodiment, the arithmetic device 1 has the feature. Therefore, in this embodiment, as the magnetic field measuring device 6, for example, a cerebral magnetic field measuring device, a pulmonary magnetic field measuring device, a muscular magnetic field measuring device, or the like can be appropriately applied.

(Inside cryostat)
FIG. 2 is a diagram illustrating a configuration example of a cryostat.
As shown in the upper part of FIG. 2, a plurality of SQUID magnetometers (cardiac magnetic signal acquisition units) 21 are arranged side by side at the bottom of the cryostat 2. Each SQUID magnetometer 21 has a coil in which a superconducting wire is wound around a bobbin, and a SQUID sensor connected to the coil in the upper part of the coil.
Each SQUID magnetometer 21 is installed so that the bottom thereof is parallel to the bottom of the cryostat 2. Then, each of the SQUID fluxmeter 21, over time to measure the magnetic field components _{B z} in the z-direction. A plurality of SQUID magnetometers 21 are arranged at equal intervals in the x and y directions in the cryostat 2 so that the amount of change in the magnetic distance can be accurately grasped. In this embodiment, the distance between the individual SQUID magnetometers 21 is 0.025 m, the measurement surface 22 is arranged in an array of 0.175 m × 0.175 m, and the number of SQUID magnetometers 21 is 8 × 8. However, it is not limited to such an arrangement.
In this embodiment, in order to avoid complication of the figure, the SQUID magnetometer 21 is expressed by 7 × 7 squares (measurement surface 22) as shown in the lower part of FIG. On the measurement surface 22, the place where the lattice intersects (8 × 8) corresponds to the place where the SQUID magnetometer 21 is arranged.

(Disposition of SQUID magnetometer during measurement)
FIG. 3 is a diagram showing the arrangement of the SQUID magnetometer at the time of measurement.
At the time of measurement, the SQUID magnetometer is arranged so that the measurement surface 22 of the SQUID magnetometer is parallel to the chest wall 33. For example, the SQUID magnetometer indicated by reference numeral 31 is positioned directly above the sword-like projection 32 of the chest. Next, the measurement surface 22 is aligned. At this time, for example, a SQUID magnetometer indicated by reference numeral 34 is set as the origin O of the coordinate system. And the measurement surface 22 becomes a magnetic field measurement region.
Note that by changing the orientation of the SQUID fluxmeter 21 coil plane (Figure 2) (measurement surface 22), and magnetic field component _{B x} in the x-axis direction can also be detected magnetic field component _{B y} in the y-axis direction.

(Configuration of arithmetic unit)
FIG. 4 is a diagram illustrating a configuration example of the arithmetic device according to the first embodiment.
The computing device 1 is a PC (Personal Computer) or the like, and includes a memory 110, a CPU (Central Processing Unit) 120, and a storage device 130 such as an HD (Hard Disk). Further, a display device (display unit) 9 such as a display for displaying information is connected to the arithmetic device 1. Furthermore, an input device (input unit) 10 such as a keyboard and a mouse is connected to the arithmetic device 1. The computing device 1 includes a transmission / reception device 140 that is connected to the amplifier filter unit 8 and receives information from the magnetic field measurement device 6 via the amplifier filter unit 8 and the drive circuit 7.
The program stored in the storage device 130 is expanded in the memory 110, and the CPU 120 executes the program expanded in the memory 110, whereby the processing unit 111, the signal input unit 112 constituting the processing unit 111, the current An arrow generation unit 113, a vector ring generation unit 114, and an input / output processing unit 115 are realized.

The processing unit 111 controls the signal input unit 112, the current arrow generation unit 113, the vector ring generation unit 114, and the input / output processing unit 115.
The signal input unit 112 acquires a magnetocardiogram signal input from the cryostat 2 via the amplifier filter unit 8 (FIG. 1).
The current arrow generator 113 generates a current arrow for each channel from the magnetocardiogram signal for each channel acquired by the signal input unit 112.
The vector ring generation unit 114 generates a magnetocardiogram vector ring based on the current arrow generated by the current arrow generation unit 113.
The input / output processing unit 115 displays the current arrow generated by the current arrow generation unit 113 and the magnetocardiogram vector ring generated by the vector ring generation unit 114 on the display device 9 or information input via the input device 10. Based on this, the current arrow and the magnetocardiogram vector ring are set.

  In the present embodiment, as an example, the magnetocardiogram signal is recorded for 30 seconds at a sampling frequency of 1 kHz and stored in the storage device 130 in the arithmetic device 1. Further, when recording the magnetocardiogram signal, a ham filter for applying a 0.1 Hz high-pass filter and a 100 Hz low-pass filter in the amplifier filter unit 8 to remove noise caused by a commercial power supply was applied. Thereafter, addition averaging processing and baseline correction processing (correction by the average magnetic field intensity during the time when no magnetocardiogram signal appears) for increasing the SN (Signal Noise) ratio of the magnetocardiogram signal stored in the arithmetic unit 1 are performed. I will do it.

FIG. 5 is a flowchart showing the procedure of the magnetocardiogram vector ring analysis process according to the first embodiment. Reference is made to FIGS. 1 and 4 as appropriate.
First, the magnetic field measurement device 6 measures a magnetocardiogram signal (measurement process: S101). The measured magnetocardiogram signal is sent to the arithmetic unit 1 via the drive circuit 7 and the amplifier filter unit 8.
Then, the current arrow generation unit 113 of the arithmetic device 1 generates a current arrow for each channel based on the magnetocardiogram signal acquired from each channel, and the current arrow generated by the input / output processing unit 115 is displayed on the display device 9. Display (current arrow generation / display processing: S102).

A current arrow diagram is used as the current arrow generated in step S102. The current arrow diagram is an analytically generated magnetocardiogram in the tangential (x and y) direction from the magnetocardiogram (B _z ) in the normal (z) direction perpendicular to the chest wall. The current vector is projected onto the measurement plane and displayed. Therefore, the current arrow projection can reconstruct the same number of current vectors as the number of measurement points, and displays the magnitude of the current vector by the length of the arrow and the direction of the current vector by the direction of the arrow. The current arrow diagram will be described later.

The current arrow generator 113 obtains the x component (I) of the current vector (I _i ) at the _i- th position (i = 1, 2,..., 64: i is the number of the SQUID magnetometer) obtained from the current arrow projection. _{x, i} ) and y components (I _{y, i} ) are calculated from equations (1) and (2) using B _{z, i} , respectively.

I _{x, i} ∝∝B _{z, i} / ∂y (1)
I _{y, i} ∝−∂B _{z, i} / ∂x (2)

Next, the input / output processing unit 115 of the arithmetic device 1 causes the display device 9 to display a mode selection screen. The user selects a mode for generating a magnetocardiogram ring via the input device 10 (mode selection process: S103). The selected mode is “average”, “maximum” or the like. Multiple modes can be selected.
Subsequently, the vector ring generation unit 114 of the arithmetic device 1 generates a magnetocardiogram vector ring for each mode (magnetomagnetic vector ring generation process: S104). The generation of the magnetocardiogram vector ring will be described later.

Then, the input / output processing unit 115 of the arithmetic device 1 displays the magnetocardiogram vector ring generated in step S104 on the display device 9 for each mode (magnetomagnetic vector ring display process: S105). The display screen in step S105 will be described later.
A channel removal button is displayed on the display screen, and it is determined whether channel removal “OK” is selected and input via the input device 10 or “NO” is selected and input. 111 determines whether or not to perform channel removal (channel removal determination processing: S106).

As a result of step S106, when channel removal is not performed (S106 → No), the processing unit 111 advances the process to step S108.
When performing channel removal as a result of step S106 (S106 → Yes), the user selects a channel (removal channel) for removal via the input device 10 (channel removal selection process: S107). The process of step S107 will be described later.

Subsequently, the processing unit 111 of the arithmetic device 1 determines whether or not to perform recalculation by determining whether or not the recalculation “OK” is selected and input via the input device 10 and “NO” is selected and input. (Recalculation determination processing: S108).
As a result of step S108, when recalculation is not performed (S108 → No), the processing unit 111 of the arithmetic device 1 ends the processing.
As a result of step S108, when recalculation is performed (S108 → Yes), the processing unit 111 of the arithmetic device 1 selects and inputs “Yes” of the mode change button via the input device 10 or “No”. By determining whether or not the mode has been changed, it is determined whether or not to change the mode (mode change determination process: S109).

As a result of step S109, when the mode is not changed (S109 → No), the processing unit 111 of the arithmetic device 1 returns the process to step S104.
As a result of step S109, when the mode is changed (S109 → Yes), the processing unit 111 of the arithmetic device 1 returns the process to step S103.

FIG. 6 is a diagram showing a method for generating a magnetocardiogram vector ring according to the first embodiment.
As shown in FIG. 6A, if the x component and the y component of the current arrow 201 at a certain time t1 are (400, −200), (400, − of the vector ring diagram 210 of FIG. 6B). 200) is plotted (plot point 211).
If the x component and the y component of the current arrow 201 at time t2 are (200, −300), a point is plotted in (200, −300) of the vector ring diagram 210 of FIG. Plot point 212).

When the above is generalized, the current arrow generation unit 113 assumes that a plurality of generated current arrows a is a = Σq _i j _i, and the magnetocardiogram vector ring showing the coefficient q _i in each current arrow as coordinates. Is generated. However, q _i is a coefficient, j _i is a unit vector: i = 1, 2, 3..., Where i = 1, 2, j ₁ is a unit vector in the x-axis direction, and j ₂ is y. An axial unit vector.

Thus, by plotting the x component and the y component of the current arrow at each time in the vector ring diagram in a time-continuous manner, the magnetocardiogram vector diagram which is the time change of the x component and the y component of the current arrow is obtained. Generated. Therefore, the angle of each point of the magnetocardiogram vector ring with respect to the origin of the magnetocardiogram vector annulus is the angle of the current arrow at each time. For example, if the current arrow component is (x1, y1), the angle θ1 of this current arrow is given by θ1 = tan ⁻¹ (y1 / x1).

FIG. 7 is a diagram illustrating a screen example according to the first embodiment.
The magnetocardiogram analysis screen 300 includes a magnetocardiogram signal display screen 310, a current arrow diagram display screen 320, and a magnetocardiogram vector ring display screen 330.

  The magnetocardiogram signal display screen 310 displays the waveform of the magnetocardiogram signal measured by the magnetic field measurement device. On the magnetocardiogram signal display screen 310 in FIG. 7, waveforms of magnetocardiogram signals acquired from each of the 64 channels are displayed in an overlapping manner. On the magnetocardiogram signal display screen 310, an analysis period can be specified. The analysis period is specified by setting a time window start line 311 and a time window end line 312. Based on the magnetocardiogram signal within the analysis period specified on the magnetocardiogram signal display screen 310, the current arrow generator 113 generates a current arrow, and the vector ring generator 114 generates a magnetocardiogram vector ring.

The current arrow diagram display screen 320 displays the current arrow in each of the 64 channels. In the current arrow diagram display screen 320, a location corresponding to the channel is indicated by a rectangle 322 in the current arrow display area 321. In each rectangle 322, a current arrow 323 generated based on the magnetocardiogram signal acquired in the channel indicated by the target rectangle 322 is displayed. That is, the current arrow diagram display screen 320 displays a total of 64 current arrows corresponding to the 64 channels.
In addition, a time designation window 324 is displayed on the current arrow diagram display screen 320. When the time is input to the time designation window 324 via the input device 10, a current arrow diagram at the input time is displayed on the current arrow diagram display screen 320. By changing the time input to the time designation window 324, a current arrow diagram at each time can be displayed. The time that can be input in the time specification window 324 is a time within the analysis period specified on the magnetocardiogram signal display screen 310.
Incidentally, the contour lines on the current arrow diagram display screen 320 indicate the magnitude (norm) of the current arrow.

  The magnetocardiogram vector ring display screen 330 displays a magnetocardiogram vector ring generated based on the measured magnetocardiogram signal. In the example of FIG. 7, an average vector ring that is a magnetocardiogram ring obtained by averaging current arrows at each time is displayed on the average vector ring display screen 340, and the maximum vector ring display screen 350 displays the maximum value at each time. A maximum vector ring which is a magnetocardiographic vector ring generated from a current arrow (maximum current arrow) is displayed. Here, the average current arrow is a current arrow having an x component and an y component obtained by averaging the x component and the y component of each current arrow (64 current arrows in the current arrow diagram display screen 320). is there. The maximum current arrow is, for example, a current arrow having a maximum norm among 64 current arrows in the current arrow diagram display screen 320.

The average vector ring shows the overall tendency of the current arrow, and the maximum vector ring shows the movement of the main current arrow. That is, the average vector ring allows the user to grasp the overall trend of the current arrow in the current arrow diagram display screen 320, and the maximum vector ring allows the user to determine the main trend in the current arrow diagram display screen 320. The movement of the current arrow can be grasped.
Here, the average vector ring is a current arrow (average current arrow) averaged at each time within the time range specified by the time window start line 311 and the time window end line 312 of the magnetocardiogram signal display screen 310. The time change of the angle is shown. The same applies to the maximum vector ring.

  The average vector ring display screen 340 displays the minimum intensity, maximum intensity, minimum angle, and maximum angle of the average current arrow. The intensity is the norm of the current arrow, and the minimum intensity is the average current arrow within the time range specified by the time window start line 311 and the time window end line 312 of the magnetocardiogram signal display screen 310. Is the minimum value of intensity. Similarly, the maximum intensity is the maximum value of the intensity of the average current arrow within the time range specified by the time window start line 311 and the time window end line 312 of the magnetocardiogram signal display screen 310.

  The minimum angle on the average vector ring display screen 340 is the highest intensity (absolute value) in the average current arrow at each time in the analysis period set by the time window start line 311 and the time window end line 312. This is the angle of the average current arrow having a small intensity. The maximum angle on the average vector ring display screen 340 is the highest intensity (absolute value) in the average current arrow at each time in the analysis period set by the time window start line 311 and the time window end line 312. This is the angle of the average vector having a large intensity.

Further, the same minimum intensity, maximum intensity, minimum angle, and maximum angle are also displayed on the maximum vector ring display screen 350.
The minimum angle in the maximum vector ring display screen 350 is the highest intensity (absolute value) in the maximum current arrow at each time in the analysis period set by the time window start line 311 and the time window end line 312. It is the angle of the maximum current arrow with a small intensity. The maximum angle on the maximum vector ring display screen 350 is the highest intensity (absolute value) in the maximum current arrow at each time in the analysis period set by the time window start line 311 and the time window end line 312. This is the angle of the maximum current arrow having a high strength.

FIG. 8 is an enlarged view of the magnetocardiogram vector ring display screen, (a) is a diagram showing an average vector ring, and (b) is a diagram showing a maximum vector ring. In FIG. 8, the vertical axis and horizontal axis values in the average vector ring display screen 340 and the maximum vector ring display screen 350 in FIG. 7 are omitted.
In both the average vector ring and the maximum vector ring, the depiction of the lines constituting the magnetocardiogram vector ring changes depending on the time.
Here, the analysis period of the magnetocardiogram vector (the period between the time window start line 311 and the time window end line 312 in the magnetocardiogram signal display screen 310 of FIG. 7) is divided into three periods (start period 401 (dashed line portion). ), An intermediate period 402 (solid line), and an end period 403 (dotted line)). In other words, the magnetocardiogram vector analysis period is shown as a period divided by a predetermined time (predetermined condition). In this manner, the input / output processing unit 115 changes the display of the magnetocardiogram vector ring according to a predetermined condition.

  In the present embodiment, the analysis period of the magnetocardiogram vector is shown as a period divided by a predetermined time, but the present invention is not limited to this. For example, the display of the magnetocardiogram vector ring may be changed depending on the intensity (norm) of the current arrow. By doing so, it is possible to easily analyze the relationship between predetermined conditions (time, current arrow strength, etc.) and the magnetocardiogram vector ring.

  In the lines constituting the magnetocardiogram vector ring, the start period is indicated by a broken line 401, the intermediate period is indicated by a solid line 402, and the end period 403 is indicated by a dotted line. Here, the period is expressed by changing the line type, but in actuality, it is indicated by color coding or the like. By dividing the periods by color, the user can easily distinguish the periods. In the present embodiment, the analysis period is divided into three periods, but may be divided into two periods or four or more periods. Moreover, the connection of each period may be shown by gradation.

  By doing so, the user can visually recognize the time change of the current arrow and, as will be described later, when the noise component is generated, it is specified in which period the noise component is generated. It becomes easy.

(Noise component removal)
Next, the noise component removal procedure will be described with reference to FIGS. In FIG. 9, as in FIG. 8, the broken line portion indicates the start period, the solid line indicates the intermediate period, and the dotted line indicates the end period.
FIG. 9 is a diagram illustrating an example of a magnetocardiogram vector ring in a P wave. (A) is an example of a magnetocardiogram vector ring in which noise is generated, and (b) is a magnetocardiogram vector ring in which noise is not generated. It is an example. The magnetocardiogram vector ring shown in FIG. 9 is an average vector ring.
From the comparison between FIG. 9A and FIG. 9B, it can be seen that noise is generated in the portion shown in the noise generation region 451. And since the code | symbol 451 contains the continuous line and a dotted line, it turns out that the noise has generate | occur | produced in the end period of an analysis period.

Next, the user inputs a time when noise is estimated to be generated in the magnetocardiogram vector ring in the time designation window 324 of the current arrow diagram display screen 320 of the magnetocardiogram analysis screen 300 shown in FIG. Thereby, the current arrow diagram display screen 320 at the time when it is estimated that noise is generated in the magnetocardiogram vector ring is displayed. In the displayed current arrow diagram display screen 320, the user removes a channel that seems to be causing noise.
To identify the channel that seems to be generating noise, specify the channel that the current arrow displayed on the current arrow diagram display screen 320 is too large or too small compared to the adjacent current arrow. It is done by doing. Alternatively, it is performed by specifying a channel or the like in which noise is likely to be generated in which the direction of the current arrow is away from the adjacent current arrow.

(Noise channel removal)
FIG. 10 is a diagram showing an example of a current arrow diagram display screen from which a channel where noise is considered to be generated is removed.
For example, in the current arrow display area 321 of the current arrow diagram display screen 320 (FIG. 7), when the user clicks on a channel, the clicked channel portion becomes blank as shown in a grid 501 in FIG. A channel corresponding to the lattice 501 that is white is a channel to be removed. In this way, channel removal is performed.
By the way, if you click the white channel again, the display is restored. That is, channel removal is cancelled.

  Thereafter, the regeneration of the magnetocardiogram vector ring is instructed via the input device 10, and the magnetocardiogram signal of the removed channel is excluded to generate the magnetocardiogram vector ring.

As described above, by enabling the removal of an arbitrary channel, a magnetocardiogram vector ring from which noise and the like are removed can be generated.
Incidentally, in the vector electrocardiogram, since all of the 12-lead electrocardiograms are necessary, it is impossible to exclude the electrocardiogram, and even if the influence of noise or the like can be confirmed, the influence cannot be removed.
In this embodiment, the channel is removed for noise removal, but the present invention is not limited to this. When a magnetocardiogram ring is generated and analyzed for a current arrow for a specific channel, channels other than the channel the user wants to view may be removed.

(Effect of magnetocardiogram vector ring)
Here, the effect of the magnetocardiogram vector ring will be described with reference to FIGS. 11 and 12, as in FIG. 8, the broken line 401 indicates the start period, the solid line 402 indicates the intermediate period, and the dotted line 403 indicates the end period.
FIG. 11 is a diagram showing an example of a magnetocardiogram vector ring related to J wave detection.
FIG. 11A shows an average vector ring of the QRS wave portion at the normal time. FIG. 11B shows an average vector ring of the QRS wave portion when an abnormality is recognized in the J wave.
In the vector electrocardiogram, it is difficult to detect the vector portion related to the J wave. However, as shown in FIGS. 11A and 11B, when the magnetocardiogram vector ring is used, normal and abnormal times are detected. Can be clearly distinguished.

Further, FIG. 11C is a diagram illustrating the heart in FIG. 11B by adjusting the period between the time window start line 311 and the time window end line 312 on the magnetocardiogram signal display screen 310 in FIG. This is a magnetocardiographic vector ring in which only the portion related to the J wave is extracted from the magnetic vector ring.
Thus, in the magnetocardiogram vector ring, the J wave appears remarkably as shown in FIG. 11B, so that the user can easily extract and analyze only the J wave as shown in FIG. 11C. .

FIG. 12 is a diagram showing an example of a magnetocardiogram ring related to the WPW syndrome.
FIG. 12A shows an average vector ring in the initial 10 ms portion of the QRS wave at the normal time. FIG. 12B shows an average vector ring in the initial 10 ms portion of the QRS wave when WPW syndrome is suspected.
As is clear from a comparison between FIG. 12A and FIG. 12B, the magnetocardiogram signal advances in the opposite direction between the normal time and the abnormal time at the early stage of the QRS wave. In the vector electrocardiogram, even when WPW syndrome is suspected, the difference is not clear.
Thus, according to the magnetocardiogram vector ring, it is possible to clearly distinguish the WPW syndrome that is unclear in the vector electrocardiogram.
The examples shown in FIGS. 11 and 12 are examples, and other diseases that are difficult to understand in the vector electrocardiogram, such as P waves that are difficult to understand in the vector electrocardiogram, are easily understood in the vector electrocardiogram. Often becomes.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, not channel removal but channel selection is performed. In addition, since each structure of the biomagnetic field measurement system Z and the arithmetic unit 1 is the same as that of 1st Embodiment, illustration and description are abbreviate | omitted in 2nd Embodiment.

(flowchart)
FIG. 13 is a flowchart showing the procedure of a magnetocardiogram vector ring analysis process according to the second embodiment. In FIG. 13, the same processes as those in FIG. 5 are denoted by the same step numbers and description thereof is omitted.
After the magnetocardiogram vector ring is displayed in step S105, a channel selection button is displayed on the display screen, and it is determined whether channel selection “OK” or “NO” is selected and input via the input device 10. Thus, the processing unit 111 of the arithmetic device 1 determines whether or not to perform channel selection (channel selection determination processing: S201).

As a result of step S201, when channel selection is not performed (S201 → No), the processing unit 111 advances the processing to step S108.
When channel selection is performed as a result of step S201 (S201 → Yes), the user selects a channel via the input device 10 (channel selection processing: S202). The process of step S202 will be described later.
Thereafter, the processing unit 111 proceeds to step S108.

(Channel selection)
FIG. 14 is a diagram illustrating an example of a current arrow diagram display screen in which a channel is selected.
For example, in the current arrow display area 321 of the current arrow diagram display screen 320, when the user clicks a channel, the clicked channel portion is highlighted as shown by reference numeral 601 in FIG.
By the way, clicking the highlighted channel again will restore the display. That is, channel selection is cancelled.

  Thereafter, when the regeneration of the magnetocardiogram vector ring is instructed via the input device 10, the magnetocardiogram vector ring is generated using only the magnetocardiogram signal of the selected channel.

In this way, by enabling the selection of channels, for example, when the number of channels with noise is large, the number of channels to be removed is increased by the method shown in the first embodiment, and the user can be selected. It may take time and effort. In such a case, by selecting a channel as in the second embodiment, even if the number of channels to be removed increases, the user's effort can be reduced.
Incidentally, in the vector electrocardiogram, since all of the 12-lead electrocardiograms are required, it is impossible to select an electrocardiogram.

  Moreover, it is desirable that the first embodiment and the second embodiment can be switched by a button or the like.

<< Third Embodiment >>
FIG. 15 is a diagram illustrating an arrangement of SQUID magnetometers at the time of measurement according to the third embodiment.
In FIG. 15, the measurement surfaces 22 a to 22 c are arranged on the front, left side, and back surface as viewed from the subject.
Each of the measurement surfaces 22a to 22c has a 64-channel SQUID magnetometer.
Since reference numerals 31 to 34 are the same as those in FIG. 3, description thereof is omitted here.

FIG. 16 is a diagram showing a magnetocardiogram vector ring screen according to the third embodiment.
FIG. 16A shows a magnetocardiogram ring generated based on the magnetocardiogram signal acquired from the measurement surface 22a of FIG. That is, it is a magnetocardiogram ring generated based on the magnetocardiogram signal measured in front from the viewpoint of the subject. FIG. 16B shows a magnetocardiogram vector ring generated based on the magnetocardiogram signal acquired from the measurement surface 22b of FIG. That is, it is a magnetocardiogram vector ring generated based on the magnetocardiogram signal measured on the left side as viewed from the subject. FIG. 16C shows a magnetocardiogram vector ring generated based on the magnetocardiogram signal obtained from the measurement surface 22c of FIG. That is, it is a magnetocardiogram ring generated based on the magnetocardiogram signal measured on the back surface as viewed from the subject.
The magnetocardiogram vector rings shown in FIGS. 16A to 16Cb are preferably displayed side by side on the same screen.

Thus, by generating a magnetocardiogram vector based on the magnetocardiogram signals measured on different planes, it is possible to analyze the magnetic field change in the heart three-dimensionally.
In addition, since the electrocardiogram used by an electrocardiogram vector needs to be measured in the decided body part, as shown to FIG. 15, FIG. 16, it cannot measure on a test subject in a different surface. Therefore, only an electrocardiogram vector for a predetermined part is generated.

In this embodiment, the magnetocardiogram ring is displayed as a still image, but the magnetocardiogram ring may be displayed as a moving image.
Further, in the present embodiment, as shown in FIG. 3, the measurement surface of the SQUID magnetometer is installed on the front side of the person to be measured, but it may be installed on the side surface and the back side of the person to be measured.
Furthermore, although the average vector ring and the maximum vector ring are shown in the present embodiment, for example, a magnetocardiogram vector ring may be generated for each channel. At this time, a channel may be selected by the method according to the second embodiment, and a magnetocardiogram vector ring may be generated for each selected channel.

  The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

Each of the above-described configurations, functions, the units 111 to 115, the storage device 130, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Further, as shown in FIG. 4, the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by a processor such as a CPU. Information such as programs, tables, and files for realizing each function is stored in an HD (Hard Disk), a memory, a recording device such as an SSD (Solid State Drive), an IC (Integrated Circuit) card, It can be stored in a recording medium such as an SD (Secure Digital) card or a DVD (Digital Versatile Disc).
In each embodiment, control lines and information lines are those that are considered necessary for explanation, and not all control lines and information lines are necessarily shown on the product. In practice, it can be considered that almost all configurations are connected to each other.

1. Arithmetic unit (cardiac magnetic field analyzer)
2 Cryostat 3 Gantry 4 Bed 5 Magnetic shield room 6 Magnetic field measuring device 7 Drive circuit 8 Amplifier filter unit 9 Display device (display unit)
10 Input device (input unit)
21 SQUID magnetometers 22, 22a, 22b, 22c Measuring surface 31 SQUID magnetometer on sword-like projection 32 Sword-like projection 33 Chest wall 34 SQUID magnetometer indicating origin 110 Memory 111 Processing unit 112 Signal input unit 113 Current arrow generation unit 114 Vector ring generator 115 Input / output processor 120 CPU
DESCRIPTION OF SYMBOLS 130 Memory | storage device 140 Transmission / reception apparatus 201 Current arrow 210 Vector ring diagram 211 Plot point 212 Plot point 300 Magneto-magnetic analysis screen 310 Magneto-magnetic signal display screen 311 Time window start line 312 Time window end line 320 Current arrow diagram display screen 321 Current arrow display Area 322 Rectangular 323 Current arrow 324 Time designation window 330 Magnetomagnetic vector ring display screen 340 Average vector ring display screen 350 Maximum vector ring display screen 401 Start period 402 Intermediate period 403 End period 451 Noise generation area 501, 601 Lattice S101 Measurement process S102 Current arrow generation / display processing S103 mode selection processing S104 magnetocardiogram vector ring generation processing S105 magnetocardiogram vector ring display processing S106 channel removal determination processing S107 removal channel selection processing S108 recalculation Arithmetic determination processing S109 Mode change determination processing S201 Channel selection determination processing S202 Channel selection processing Z Cardiac magnetic field analysis system (cardiac magnetic field analysis system)

Claims (11)

A current arrow generator for generating a plurality of current arrows a, which are vectors of current flowing in the cardiac magnetic field, from the magnetocardiogram signal measured by the magnetocardiograph;
When the plurality of generated current arrows a are a = Σq _i j _i (where q _i is a coefficient and j _i is a unit vector), the magnetocardiogram vector ring showing the coefficient q _i in each current arrow as coordinates. A vector ring generator for generating
A display processing unit for displaying the generated magnetocardiogram vector ring on a display unit;
An electrocardiogram analyzing apparatus comprising: The display processing unit
The magnetocardiogram analysis apparatus according to claim 1, wherein the display of the magnetocardiogram ring is changed according to a predetermined condition. The current arrow generation unit includes:
Generate the current arrow at each time,
The vector ring generator is
Generating the magnetocardiographic vector ring at each time;
The input / output processor is
The magnetocardiogram analysis apparatus according to claim 2, wherein the display of the magnetocardiogram vector ring is changed according to a predetermined condition by changing the display of the magnetocardiogram vector ring according to the time. The input / output processor is
The magnetocardiogram analysis device according to claim 3, wherein the display of the magnetocardiogram vector ring is changed according to the time by changing the color of the magnetocardiogram vector ring according to the time. The magnetocardiogram signal is acquired from a plurality of magnetocardiogram signal acquisition units,
The current arrow is generated by the generation unit.
At each time, based on the magnetocardiogram signal acquired from each magnetocardiogram signal acquisition unit, to generate the current arrow corresponding to each magnetocardiogram signal acquisition unit,
The vector ring generator is
The magnetocardiogram analysis apparatus according to any one of claims 1 to 4, wherein the magnetocardiogram vector ring is generated based on an average current arrow obtained by averaging a plurality of the current arrows at a certain time. . The magnetocardiogram signal is acquired from a plurality of magnetocardiogram signal acquisition units,
The current arrow is generated by the generation unit.
At each time, based on the magnetocardiogram signal acquired from each magnetocardiogram signal acquisition unit, to generate the current arrow corresponding to each magnetocardiogram signal acquisition unit,
The vector ring generator is
The magnetocardiogram vector ring is generated based on a maximum current arrow having a maximum size among the plurality of current arrows at a certain time. The described magnetocardiogram analyzer. When an arbitrary current arrow is selected from the plurality of current arrows via the input unit,
The vector ring generator is
The magnetocardiogram analysis apparatus according to any one of claims 1 to 6, wherein the magnetocardiogram vector ring is generated by excluding the selected current arrow. When an arbitrary current arrow is selected from the plurality of current arrows via the input unit,
The vector ring generator is
The magnetocardiogram analysis apparatus according to any one of claims 1 to 6, wherein the magnetocardiogram vector ring is generated based on the selected current arrow. The magnetocardiogram signals are acquired from the front, left and back sides of the subject;
The vector ring generator is
7. The magnetocardiogram vector ring is generated based on respective magnetocardiogram signals acquired from the front, left side, and back side of the subject. 7. Cardiac magnetic field analyzer. A magnetocardiograph for measuring a magnetocardiogram signal of a living body;
A magnetocardiogram analyzer for generating a magnetocardiogram vector ring from a magnetocardiogram signal measured by the magnetocardiograph;
A cardiac magnetic field analysis system comprising:
The cardiac magnetic field analyzer is
A current arrow generator for generating a plurality of current arrows a, which are vectors of current flowing in the cardiac magnetic field, from a magnetocardiogram signal measured by the magnetocardiograph;
When the plurality of generated current arrows a are a = Σq _i j _i (where q _i is a coefficient and j _i is a unit vector), the magnetocardiogram vector ring showing the coefficient q _i in each current arrow as coordinates. A vector ring generator for generating
A display processing unit for displaying the generated magnetocardiogram vector ring on a display unit;
A cardiac magnetic field analysis system characterized by comprising: A magnetocardiogram analyzer that generates a magnetocardiogram vector ring from a magnetocardiogram signal obtained from a magnetocardiograph
A plurality of current arrows a, which are vectors of current flowing in the cardiac magnetic field, are generated from the magnetocardiogram signal measured by the magnetocardiograph,
When the plurality of generated current arrows a are a = Σq _i j _i (where q _i is a coefficient and j _i is a unit vector), the magnetocardiogram vector ring showing the coefficient q _i in each current arrow as coordinates. Produces
Displaying the generated magnetocardiogram vector ring on a display unit.

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